Controlling apparatus for propeller blades



Oct. 5, 1937. G. DALTON 2,094,838

CONTROLLING APPARATUS FOR PROPELLER BLADES Filed April 4, 1936 2 Sheets-Sheet l INVENTOR. m fiww,

1 ATTORNEYS. 1

Oct. 5, 1937. e. DALTON CONTROLLING APPARATUS FOR PROPELLER BLADES Filed April 4, 1936 2 Sheets-Sheet 2 7 B 9 a N H I V IFH IN VEN TOR. BY 5 Patented Oct. 5, 1937 UNITED STATES PATENT OFFICE CONTROLLING APPARATUS'FOR I PROPELLER BLADES My invention relates to controlling apparatus for propeller blades and process for. controlling same.

The objects of my invention are to provide a process and means actuated by centrifugal force to increase or vary the pitch of the propeller blades of a propeller driven vehicle, particularly airplanes; to provide manual controlling means to overcome resistance to such increase or variation of pitch; and to provide means for giving the tip of a propeller blade a certain amount of lead over the heel of the blade to increase the effectiveness of the blades when the pitch thereof is increased.

I attain these objects by the means illustrated in the accompanying drawings, in which Figure 1 is a side elevation of a propeller hub withmy apparatus attached, partly in section on the middle line;

Figure 2 is a sectional elevation on the line, 2-2, of Figure 3;

Figure 3 is a longitudinal section on the line, 3-3, of Figure 2;

Figure 4 is a detail showing the locking groove in the shank of one of the blades;

Figure 5 is a similar detail, but showing the shank with a quarter turn from the position shown in Figure 4;

section.

Similar numerals refer to similar parts throughout the several views.

My apparatus comprises a propeller hub, 4, rigidly mounted upon the front end of theengine shaft. This hub. is of general cylindrical form,

40 other suitable means and are provided with bear- I ings, 5c, to facilitate the turning thereof.

The central portion of the hub, 4, is bored out to receive a cylinder, Ill, the inner end of which is mounted upon the outer end of the engine shaft,

2, and the cylinder, l0, and the hub, d, are looked upon the engine shaft, 2, by a castellated nut, 2a, and thespline or key, 2 l.

Within the cylinder, I0, is slidably mounted a piston, I i, the outer end of which is provided with piston rings, Ila, and the inner end of which is provided with opposed channels formed therein, into which the yokes, it, formed upon the inner ends of the bell crank levers, it, extend. The yokes, it, embrace rollers, l8, mounted upon pivot 55-. pins, ll, secured in $ll tfible flanges, l lb, formed,

Figure 6 is an enlarged detail of the piston in integral with the piston, i i The bell crank levers,

l d, are rigidly secured upon the shanks, 5a, of the blades, by the tapered pins, l9, and can be locked. with the eastellated nuts, 20, or other suitable means.

The outer arms of the bell crank levers, it, extend forwardly and inwardly from their mountings ,upon the shanks and have united thereto at their outer ends semi-circular weighted heads, it, which when in idleposition, fit rather closely to the outside of the wall of the cylinder, ill, but are free to move outwardly within certain limits when acted upon by the centrifugal force developed by revolution of the engine shaft and hub and when moved outwardly by said centrifugal force will necessarily act to throw the piston, ll, forward within the cylinder, Ill.

The cylinder, I II, is provided with a cylinder head, 8, united to the cylinder by stud bolts, 9, and a semi-conical shield or guard, 6, is provided to enclose the front endof the hub, 4, and the cyl inder and bell crank levers. The front of the shield, 6, may be secured between the cylinder head, 8, and the cylinder, I0. An adjusting screw,

. I 3, is provided which is formed integral with a seat, l2, upon which one end of the compression spring, IZw, is seated and the opposite end of the spring, l2a, bears against the outer end of the piston, H, with a tension which may be varied by adjusting the screw, l3. An additional housing or shield, I, is provided which is a. thin metal plate extending over the tension screw, l3, and the edges of which may be secured by the stud bolts, 9, tothe cylinder head, 8.

It is obvious that when the engine is run at high speed, turning the propeller in the direction shown by the arrows in Figure 2, the weights, l5, upon the bell crank levers, will tend to move outwardly, thus turning the shanks, 5a, of the blades so as to increase the pitch thereof. It is also obvious that this turning movement will be resisted. by the spring, I 2a., bearing against the piston, H.

In order to reduce the restraining force of this spring and afford means by which the increase of pitch of the propeller blades may be assisted by manual control, I provide a vacuum system by which the air from the cylinder, it, can be withdrawn into the intake manifold, 3i. This system comprises a conduit including a copper tube, 2 B, one end of which opens into the cylinder, id, and the other end of which connects with a conduit or bore, 2 8a, formed in the hub, t, which leads to the annular open space, 25, surrounding the crank shaft.

An intermediate plate or body, 3, is interposed between the crank case head, I, and the rear end of the hub, 4. The channel, 25, extends both into the hub, 4, and the body, 3, surrounding the engine shaft.

A bore, 25', formed in the body, 3, conducts the air from the channel, 25, to one end of the tube, 26, which leads the air in turn to the valve housing, 21, whence it passes, through the tube, 30, to the intake manifold, 3 I.

The needle valve, 28, is mounted in the housing, which can be manually operated by the handle, 29, so as to close or open the air passage through the valve housing, 21.

In order to seal the air passage against leakage, a packing ring, 32, V-shaped in section, is mounted in a suitable annular groove in the rear face of the hub, 4, with a plurality of springs, 33, mounted in a suitable bore in the body, 3, to hold the ring, 32, tightly in the annular grooves, an annular plate, 34, being inserted between the V-ring and the adjacent ends of the springs, 33. Likewise, a packing ring, 36, may be inserted between the body, 3, and the inner member of the ballbearings, 23, mounted between the head of the crank-case, l, and the engine shaft, 2, which has the crank, 2a, formed integral therewith.

The shanks, 5a, of ,the blades, 5, may be made hollow as shown in Figures 4 and 5, in order to lighten their weight.

It is obvious that the apparatus may be so adjusted as to have the blades at any desired pitch when standing still, either for forward travel or in reverse. When adjusted to stand in reverse when idle, the air valve can be opened as soonas the engine is started and a moderate engine speed will give suflicient centrifugal force to change the pitch of the blades into forward movement.

The strength and position of the spring, l2a, may be so adjusted as to resist any movement of the piston until the desired engine speed has been attained and if it is desired to increase the pitch before such speed has been attained, it can be done by opening the air valve, 28.

It is likewise obvious that the apparatus may be so adjusted that the blades may be thrown into reverse position by relatively slow movement of the engine, so that such reverse position may be utilized to slow down an airplane in landing.

With the offset blades turning in the direction shown by the arrows in Figure 2, it is apparent that the outer ends or tips of the blades will have a certain lead over the base or heel thereof. It is believed that this lead will have an important tendency to drive the air toward the hub or to pack it in that direction, thereby overcoming to some extent the effect of centrifugal force upon the air which would tend to cause the air to fly off radially to the hub, and this packing effect should be of material assistance in driving the airplane forward.

It is obvious that my invention may be applied, with some modifications, to the propeller of a boat and I do not limit my claims to airplanes, but

apply them broadly to propeller driven vehicles of any type to which my invention may be adapted. In the operation of my device, the needle valve,

28, will normally be closed. When the engine is started in the ordinary way, the rotation. of the propellers at slow speed will not develop sumcient centrifugal force in the weights, l5, to vary the pitch of the blades, but when a predetermined high rate of speed has been reached so that the passage of the airplane through the air will permit and demand an increased pitch of the blades, the centrifugal force acting upon the weights, l5, will carry them outwardly radially, thus causing the levers, M, to turn the shanks of the blades to which they are rigidly attached. At the same time, the inner arm of the bell crank lever will carry the piston, I l, forward against the pressure of the spring, l2a, which may be adjusted to furnish the desired degree of resistance.

In case the operator wishes to increase the pitch of the blades by manual control, he then opens the valve, 28, and the suction in the intake manifold, 3i, exhausts the air from the cylinder, in, and tends to draw the piston, ll, forward in the cylinder, I, thus overcoming to the extent of the pull of the vacuum, the resistance of the spring, l2a. When the air valve, 21, is closed, a slow leakage will take place around the piston, II, which will allow air to gradually enter the cylinder and destroy the vacuum, it not being necessary nor practical to fit the pistons so tightly in the cylinder as to entirely prevent such leakage.

I do not limit my apparatus to any specific kind of material, but prefer the use of light alloys for all of the parts in which such alloys can be utilized, except the weights, l5, which should be formed of steel or even of some heavier metal or alloy.

It is obvious that various changes may be made in the size, proportion and arrangement of the parts and various equivalents may be substituted and I do not limit my claims to the precise details shown in the drawings.

While my apparatus is primarily designed for use in connection with propellers, it is obvious that with slight modifications it may be made applicable to automobile fans for the purpose of reducing the pitch of the blades in order to reduce the power required to drive a fan at high speed. I

I claim:

1. In an airplane engine, a mechanism to vary the pitch of the propeller blades automatically at predetermined engine speeds, comprising a hub mounted upon the engine shaft, a cylinder rigidly mounted in the' front of the hub, a close-fitting. piston slidingly mounted in the cylinder, a cylinder head detachably mounted upon the front end of the cylinder, a compression spring within the cylinder between the piston and the cylinder head adapted to exert increasing pressure upon the piston as the piston travels forward in-the cylinder, a plurality of spaced mutually off-set blades having their shanks pivotally mounted upon the hub, opposed slots or openings in the cylinder walls adjacent the rear end of the piston, corresponding openings in the sides of the piston skirt, bell crank levers rigidly united at their elbows to the shanks of the blades respectively with outer arms extending forwardly and weighted and with their inner arms extending through the slots of the cylinders respectively, means for connecting the inner arms of the bell crank levers to the pistons adapted to cause the pistons to travel forwardly asthe centrifugal force exerted when the hub is revolved moves the weighted ends of the outer arms outwardly and means to withdraw the air from the cylinder ahead of the piston.

2. In an airplane engine, a mechanism to vary the pitch of the propeller blades automatically at predetermined engine speeds, comprising a hub mounted upon the engine shaft, a cylinder rigidly mounted in the front of the hub, a close-fitting piston having compression rings seated in grooves withdraw the air from the cylinder ahead of the near the front end thereof, slidingly mounted in the cylinder, a cylinder head detachably mounted upon the front end of the cylinder, a com pression spring within the cylinder between the piston and the cylinder head adapted to exert increasing pressure upon the piston as the piston travels forward in the cylinder, a plurality of opposed mutually off-set blades having their shanks pivotally mounted upon the hub, opposed slots oropenings in the cylinder walls adjacent the rear end of the piston, corresponding openings in the sides of the piston skirt, bell crank levers rigidly united at their elbows to the shanks of the blades respectively with outer arms extending forwardly and weighted and with their inner arms extending through the slots of the cylinders respectively, means for connecting the inner arms of the bell crank levers to the pistons'adapted to cause the pistons to travel forwardly as the centrifugal force exerted when the hub is revolved moves the weighted ends of the outer arms outwardly, and manually controllable means to withdraw the air from the cylinders ahead of the piston.

3. In an airplane engine, a mechanism to vary the pitch of the propeller blades automatically at predetermined engine speeds, comprising a hub mounted upon the engine shaft, a cylinder rigidly mounted in the front of the hub, a close-fitting piston slidingly'mounte'd in the cylinder, a cylinder head detachably mounted upon thefront end of the cylinder, a compression spring within the cylinder between the piston and the cylinder head adapted to exert'increasing pressure upon the piston as the piston travels forward in the cylinder, a plurality of opposed mutually off-set blades having their shanks pivotally mounted upon the hub, opposed slots or openings in the cylinder walls adjacent the rear end of the piston, corresponding openings in the sides of the piston skirt, bell crank levers rigidly united at their elbows to the shanks of the blades respectively with outer arms extending forwardly and weighted and with their inner arms formed into forks extending through the slots of the cylinders respectively and adapted to engage pins secured in the slots of the pistons and cause the pistons to travel forwardly as the centrifugal force exerted when the hub is revolved moves the weighted ends of the outer arms outwardly and means to piston.

4. In an airplane engine, a manually controllable mechanism to vary the pitch of the propeller blades at various engine speeds, comprising a hub mounted upon the engine shaft, a cylinder rigidly mounted in the front of the hub, a. closefltting piston slidingly mounted in the cylinder, a cylinder head detachably mounted upon the front end of the cylinder, a compression spring within the cylinder between the piston and the cylinder head adapted to exert increasing pressure upon the piston as the piston travels forward in the cylinder, a plurality of opposed mutually off-set blades having parallel shanks pivotally mounted upon the hub, valve controlled means connecting the interior of the cylinder to the intake manifold of the engine adapted. to exhaust the air from the cylinder when the valve is opened, and weighted bell-crank levers united to the blades and the piston adapted to be actuated by centrifugal force to turn the blades in the hubs and increase the pitch thereof as the piston moves forward in the cylinder.

5. In an airplane engine, a manually controllable mechanism to vary the pitch of the propeller blades at various engine speeds, comprising a hub mounted upon the engine shaft, a cylinder rigidly mounted in the front of the hub, a closefitting piston slidingly mounted in the cylinder, acylinder head detachably mounted upon the front end of the cylinder, a compression spring within the cylinder between the piston and the cylinder head adapted to exert increasing pressure upon the piston as the piston travels forward in the cylinder, a plurality of opposed offset blades having their shanks pivotally mounted upon the hub, opposed slots or openings in the cylinder walls adjacent the rear end of the piston, corresponding openings in the sides of the piston skirt, bell crank levers rigidly united at their elbows to the shanks of the blades respectively with outer arms extending forwardly and weighted and with their inner arms extending through the'slots of the cylinder and the openings in the piston skirt respectively, manually controllable means for exhausting the air from the cylinder, and means operatively connecting the piston to the bell crank levers adapted to turn,

the blades on their pivots when the piston moves forwardly in the cylinder.

GREEN DALTON. 

